The present invention refers to a mobile chair, in the first hand adapted for used by handicapped persons in sail-boats, where it is essential for the person handling the sails to be able to move forwards and aftwards, and also rapidly to shift position from port to starboard, and vice versa. The invention is however not limited to this field of use, but may be used also in other surroundings, for instance at a working machine. The aim of the invention is thus to provide a mounting for the chair permitting movement forwards and back, as well as permitting a rotational movement of at least a half turn in arbitrary forward/aft position.